When a Long Term Evolution (LTE) page is received by a dual-sim-dual-standby (DSDS) mobile communication device supporting Voice over LTE/Video Telephony (VoLTE/VT) service, the mobile communication device may not understand whether the page is for a normal packet switched (PS) call or for a VoLTE/VT call. Therefore, the mobile communication device cannot prioritize the page response. Accordingly, the page response could be delayed and result in VoLTE/VT call setup failure.
As an example, a first LTE subscription (Sub1) may receive a PS page for a VoLTE call. However, the mobile communication device may not know the purpose of the page (i.e., for a PS call or for a VoLTE/VT call). At the same time, a second LTE subscription (Sub2) may be attempting to establish a PS call and may be controlling the transceiver resources. Therefore, Sub1 may need to wait for the Sub2 call establishment procedure to complete before responding to the (VoLTE) page. As a result of the delay, VoLTE call setup may fail. Alternatively, Sub1 may preempt the Sub2 activity to respond to the page. However, it is unnecessary to always permit the mobile communication device to preempt an activity on one subscription to receive an LTE page on the other subscription, for example when the page is for a normal PS call, since PS call setup can generally tolerate longer delay.
As another example, a first LTE subscription (Sub1) may receive a PS page which is actually for a PS call. However, the mobile communication device may not know the purpose of the page (i.e., for a PS call or for a VoLTE/VT call). At the same time, a second LTE subscription (Sub2) may be performing circuit switched (CS) (i.e., voice call) registration by sending a location area update (LAU) to the network. If Sub1 is given higher priority than Sub2 to respond to the page, Sub1 acquires control of the transceiver resources which may cause CS registration for Sub2 to fail, effectively blocking the voice call on Sub2.